PubMed Health⌕ Search

Biomedical subjects

E M Jackson

Publications and source records attributed to E M Jackson.

13 recordsLinked to original sources
PubMed1992

Effects of dietary cholesterol, type of fat, and sex on bile lipid composition of adult baboons.

We measured the effects of dietary cholesterol (0.24 vs 0.0024 mg/kJ), type of dietary fat [saturated, a ratio of polyunsaturated to saturated fatty acids (P:S) of 0.37, vs unsaturated (P:S of 2.2)], and sex on biliary lipid and bile acid conjugate composition of 80 adult pedigreed baboons. From these data we calculated the bile cholesterol saturation index and the bile acid hydrophobicity index. Dietary cholesterol significantly increased the bile cholesterol concentration by 25% and the bile cholesterol saturation index by 15%, but did not significantly affect the bile acid conjugate composition or the bile acid hydrophobicity index. Diets high in saturated fatty acid compared with unsaturated fatty acid significantly decreased the bile cholesterol concentrations by 26% and the saturation index by 23%. Saturated fatty acid also decreased the proportion of hydrophobic bile acids and lowered the bile hydrophobicity index. Male baboons had a higher cholesterol saturation index and a lower hydrophobicity index than females. Dietary cholesterol and saturated fatty acid independently influence the bile lipid composition and the cholesterol saturation index.

Animals↗
PubMed1992

Dietary cholesterol and type of fat differentially affect cholesterol metabolism and atherosclerosis in baboons.

This study was designed to determine the differences in cholesterol metabolism due to dietary cholesterol and type of fat in adult baboons. From weaning at 16 wk to 7-8 y of age, 80 baboons were fed one of four diets: high cholesterol (0.24 mg/kJ) or low cholesterol (0.0024 mg/kJ) with 40% of energy from saturated fat [polyunsaturated/saturated fatty acid ratio (P/S) = 0.37] or unsaturated fat (P/S = 2.1). High cholesterol and saturated fat independently raised serum lipoprotein and apolipoprotein concentrations to about the same extent. The liver cholesterol concentration of baboons fed high cholesterol diets was 23% higher than that of baboons fed low cholesterol. High dietary cholesterol also increased bile cholesterol concentration by 25%, the neutral steroid excretion rate by 66% and the bile acid excretion rate by 30%. With feeding of saturated fat, compared with unsaturated fat, liver cholesterol was 24% lower, bile cholesterol 26% lower and the neutral steroid excretion rate 12% lower. Dietary cholesterol greatly suppressed whole-body cholesterol synthesis, but type of fat did not affect cholesterol synthesis rate. These results suggest that dietary cholesterol and saturated fat increase plasma lipoprotein concentrations through different physiological mechanisms.

Animals↗
PubMed1992

Effect of energy intake on postprandial plasma hormones and triglyceride concentrations in infant female baboons (Papio species).

We previously reported that female baboons overfed during infancy were not fatter at weaning, but developed hypertrophic obesity after puberty. To clarify the mechanisms of this dietary effect on adipocyte hypertrophy, we determined the effects of infant overfeeding on preweaning plasma hormone and triglyceride levels and their relationship with fat cell volume at weaning (19 weeks of age). Newborn female baboons from 3 sires and 24 dams were fed either 280 kilojoules (normally fed; n = 12) or 395 kilojoules (overfed; n = 10) per 100 g Similac formula for 18 weeks. Both formulas contained 9.2%, 43.1%, and 48.5% of calories as protein, carbohydrate, and fat, respectively. During the first 9 weeks, overfed infants had significantly higher fasting and postprandial insulin, total T3, and free T3 concentrations; lower cortisol levels; and lower excretion of urinary 17-hydroxycorticosteroids (17-OHCS) than normally fed infants. These effects were no longer significant at 17-18 weeks. Infant diet did not influence fasting and postprandial plasma triglyceride levels, and fat cell volume was not influenced by energy intake. However, fat cell volume was positively associated with postprandial triglyceride concentrations and inversely associated with postmeal nadir cortisol levels. These results demonstrate that infant overfeeding initiates early alterations in insulin, T3, free T3, and cortisol, but these effects persist only as long as there is a significant increase in energy intake.

17-Hydroxycorticosteroids↗
PubMed1992

Facial moisturizers and wrinkles.

Facial moisturizers are part of the cosmetic category known as skin care products, which also includes other facial products such as astringents, toners, soaps, and bath products. This article describes the composition and pharmaceutics of currently marketed moisturizers, the use of fragrances and preservatives in these products, how cosmetic facial moisturizers work on wrinkles, sunscreen-containing facial moisturizers, and the Food and Drug Administration's record regulating drug claims for anti-wrinkling products.

Cosmetics↗
PubMed1991

Bile composition of adult baboons is influenced by breast versus formula feeding.

We tested the hypothesis that infant cholesterol intake and breast- versus formula-feeding influence the bile cholesterol saturation index and bile acid conjugate composition in adult baboons at 7-8 years of age. We also measured the influence of the postweaning intake of dietary cholesterol and fat (saturated and unsaturated) on the effects of the infant diets. The 80 baboons were derived from six sires and 80 dams and randomly assigned at birth to breast-feeding or to one of three formulas containing about 2, 30, or 60 mg cholesterol/dl. After weaning at 16 weeks of age the animals were assigned to one of four adult diets, which contained 0.01 or 1.0 mg/kcal of cholesterol containing 40% of calories from saturated or unsaturated fat. The bile cholesterol saturation index was significantly higher at 7-8 years of age in baboons breast-fed as infants compared with those fed formula (87.0% versus 72.8%, p less than 0.004). The cholesterol saturation index was not significantly different among the three formula groups. Among baboons who were breast-fed and subsequently fed saturated fat as adults, the glycine/taurine (G/T) ratios of the bile acid conjugates were about three times those of baboons fed unsaturated fat (1.53 versus 0.47); whereas among formula-fed animals the type of fat did not influence the G/T ratio (interaction, p = 0.022). Adult baboons fed the three formulas in infancy had an inverse relationship of the G/T ratio to the level of formula cholesterol (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Maternal weight and sire group, not caloric intake, influence adipocyte volume in infant female baboons.

We tested the hypothesis that overfeeding with a high caloric (concentrated) formula increases growth without influencing adipocyte volume in preweaning infant baboons. Female infant baboons from three sires and 25 dams were fed either 67.5 kcal (normal formula) or 94.5 kcal (concentrated formula)/100 g Similac formula. Immediately before weaning (19 wk), adipocyte volume was measured in biopsied adipose tissue from omentum, flank, and popliteal depots. From birth until weaning, infants fed the concentrated formula consumed 20% more total calories, averaged 15% more calories/kg/wk, and gained 14% more weight than normally fed infants. Adipocyte volume differed significantly among different sites (omentum greater than popliteal greater than flank) and among different sire groups. Increased caloric intake alone did not increase adipocyte volume. There was a small but significant sire by infant formula interaction on adipocyte volume. When fed the concentrated formula, progeny from one sire had larger adipocytes than normally fed infants, whereas progeny from the other two sires had smaller adipocytes or adipocytes that were comparable to infants fed normal formula. Variability in adipocyte volume at 19 wk of age was best accounted for by maternal weight and sire group (omentum R2 = 0.334, p = 0.026; flank R2 = 0.532, p = 0.01; popliteal R2 = 0.482, p = 0.01) and not by caloric intake. These results suggest that the level of triglyceride deposition into adipocytes attained during preweaning growth is determined to a greater extent by genetic and other factors rather than caloric intake.

Adipose Tissue↗
PubMed1990

Cholesterol metabolism in adult baboons is influenced by infant diet.

We tested the hypothesis that preweaning diet alters cholesterol metabolism in adult baboons. Eighty baboons, progeny of 6 sires and 80 dams, were either breast-fed or fed one of three infant formulas containing 2, 30 or 60 mg cholesterol/100 mL. At 16 wk of age the baboons were weaned to one of four diets containing 1.0 or 0.01 mg cholesterol/kcal with 40% of energy from saturated [polyunsaturated fat/saturated fat [P/S) = 0.37] or unsaturated fat [P/S = 2.1] and maintained on these diets until they were necropsied as young adults at 7-8 yr of age. We observed no significant effects of formula cholesterol content on serum lipid or lipoprotein concentrations measured at 6-8 yr of age, but formula cholesterol intake influenced the cholesterol turnover rate and several variables of cholesterol metabolism in the adult. At 6-8 yr, baboons that were breast-fed during infancy, compared with those that were formula-fed, had lower high-density lipoprotein cholesterol (HDL-C) concentrations and higher ratios of very-low-density plus low-density lipoprotein cholesterol (VLDL + LDL-C) to HDL-C. Breast-fed baboons, as adults, had lower cholesterol production rates, masses of the rapidly exchanging cholesterol compartment (pool A) and neutral steroid excretion rates than did those fed formula as infants. Breast and formula feeding differentially influenced the adult metabolic responses to dietary cholesterol or fat saturation. These results demonstrate that breast vs. formula feeding in infancy alters cholesterol metabolism and serum lipoprotein concentrations in adult baboons.

Aging↗
PubMed1990

Feeding influences plasma cortisol levels during preweaning life in baboons.

The effect of feeding on plasma cortisol concentrations was examined in neonate (preweaning), infant (postweaning), and adult baboons (Papio cynocephalus). Neonates were bottle fed four times daily, infants twice daily, and adults once daily. In neonates, plasma cortisol declined within 30 min after feeding. This decline in plasma cortisol was dependent on ingestion of formula and was independent of the time of feeding. During the day, cortisol fluctuations were synchronized with feeding times: peak levels occurred before feeding and trough levels occurred 30-60 min after feeding. Plasma adrenocorticotropic hormone (ACTH) declined within 30 min after feeding but returned to prefeeding levels at 60 min after feeding and did not exhibit significant variation associated with feeding times as did cortisol. The decline in plasma cortisol after feeding in neonates was delayed with increasing age. By 18 wk, the feed-related decline in plasma cortisol was delayed until 60 min after feeding compared with 30 min at age of 8 wk. After weaning, the decline in plasma cortisol after feeding was delayed until 90 min, and there was no effect of feeding in the afternoon on plasma cortisol. Finally, there was no significant decline at all in adult baboons greater than 6 yr of age. These results demonstrate plasma cortisol concentration is associated with feeding in neonates fed formula. The cortisol-feeding rhythm changes before weaning, and after weaning it begins to disappear, until it is completely absent in adults.

Adrenocorticotropic Hormone↗
PubMed1989

Inhibitors of sterol synthesis. Metabolism of [2,4-3H]5 alpha-cholest-8(14)-en-3 beta-ol-15-one after oral administration to a nonhuman primate.

5 alpha-Cholest-8(14)-en-3 beta-ol-15-one is a potent inhibitor of cholesterol biosynthesis which has significant hypocholesterolemic activity upon oral administration to rodents and nonhuman primates. In the present study the metabolism of the 15-ketosterol has been investigated after the oral administration of a mixture of [2,4-3H]5 alpha-cholest-8(14)-en-3 beta-ol-15-one and [4-14C]cholesterol to 8 baboons. Blood samples were obtained at 4, 8, 12, 16, and 24 h after administration of the labeled sterols. Clear differences in the time courses of the levels of 3H and 14C in plasma were observed. 3H in plasma showed maximum values at 4 to 8 h, whereas maximum values for the levels of 14C were observed much later. 3H in plasma was shown to be primarily in the form of its metabolites, i.e. esters of the 15-ketosterol, cholesterol, and cholesteryl esters. The levels of the 15-ketosterol and of each of these metabolites showed different changes with time. The labeled cholesterol (and the cholesterol moiety of the cholesteryl esters), formed from the [2,4-3H]-15-ketosterol, was characterized by chromatography and by purification by way of its dibromide derivative. At 24 h after the administration of the labeled sterols, the distribution of 3H in plasma lipoprotein fractions paralleled that of 14C, with most of the 3H and 14C in high density lipoprotiens (HDL) and low density lipoproteins (LDL). Almost all of the 3H in HDL and in LDL was found as cholesterol, cholesteryl esters and esters of the 15-ketosterol. The distribution of 3H in HDL and in LDL of the free 15-ketosterol, esters of the 15-ketosterol, cholesterol, and cholesteryl esters was similar to that of plasma, thereby indicating no unusual concentration of any of the 3H labeled components in HDL or LDL.

Administration, Oral↗
PubMed1989

Chronic dietary fat and cholesterol inhibit the normal postprandial stimulation of plasma cholesterol metabolism.

The response of parameters of plasma cholesterol metabolism was studied in baboons adapted either to a low-fat, low-cholesterol diet or a high-fat, high-cholesterol diet. Animals adapted to the low-fat diet responded to a single low-fat or high-fat meal, as do normal humans, by a stimulation of cholesterol transport from blood cells to plasma, a stimulation of esterification of cholesterol, and a stimulation of cholesteryl ester transfer to very low and low density lipoproteins. While fasting rates of esterification and transfer increased as a result of diet-induced hypercholesterolemia, the postprandial response was reversed, so that postprandial metabolism was characterized by a movement of cholesterol from plasma to blood cells, an inhibition of cholesterol esterification, and a net transfer of cholesteryl esters from VLDL and LDL to HDL. These data indicate that the effects of postprandial lipemia on plasma cholesterol metabolism critically depend upon fasting plasma cholesterol levels.

Animals↗